1. Field of the Invention
The invention relates to a method of automatically optimizing the video recording bias for a video signal recorded in the same tracks as an audio signal, the audio signal being stored in the deeper layers of the record carrier in a first recording step and the video signal being stored in the upper layers of said record carrier in a second recording step. The invention also relates to an arrangement for carrying out the method.
2. Description of Related Art
"Grundich Technische Informationen", Feb. 3, 1985, pp. 63-98, describes a video recorder operating in accordance with the "multi-layer recording method". This recording method is realized by arranging the audio heads approximately 90.degree. before the video heads on a head disc. During recording, the audio track is first recorded in a "deep" layer of the magnetic tape. The audio signal is subsequently overwritten at the tape surface by the following video head. The video recording bias should now be selected in such a way that the (frequency-modulated) audio signal already recorded is not attenuated excessively. The constant video recording bias to be adjusted during final adjustment of the video recorder may therefore be only so large as to ensure that the audio signal is not attenuated too strongly, allowance being made for different types of tape and other tolerances in the recording system. Consequently, the picture information is not always recorded with an optimum video recording bias.
German Offenlegungsschrift 27 58 307 reveals a method of automatically optimizing the video recording bias for a video signal. For this purpose, the video recording bias is increased preferably linearly, the playback signal is differentiated and for a selected gradient of the playback signal, the value of the video recording bias is determined and stored. However, this method exclusively relates to the optimization of the video recording without any attention being paid to the associated audio recording.